Ch. 7 Conducting a Good Experiment

Question 1

Types of Participants

Answer 1

When conducting an experiment it can be difficult deciding what participants would be best. There are 3 things to consider that will make this easier.

• PRECEDENT – If your literature review indicates that researchers have worked with a particular type of participant successfully in prior research projects in your area of interest, you may want to consider using this type of participant.
  
  • Being able to draw on this body of already proven techniques means the likelihood of success is increased.
  • However, the continual use of one type or species of participant can limit the generalizability of the information that is gathered.
  • Ex) in 1901 Willard S. Small conducted the first rat study in the US. In doing so he set a precedent or an established pattern that continues to this day
• Similarly, this is why we so often see college students as participants in studies.
• Because one type of participant is used continuously, it ensures that a body of knowledge exists about that type of participant. Being able to draw on this body of already proven techniques increases the likelihood of success.
• The continual use of one type or species of participant can limit the generalizability of the information that is gathered (External validity).
• AVAILABILITY – Rats and college students are cheap and readily available.
  
  • Often times with college students (often psych students), participating in a study is a course requirment which ensures the availability of participants.
  • Availability does not guarantee the researcher chose the best or most appropriate participants.
• TYPE OF RESEARCH PROJECT – Often the nature of your research project will determine the type of participant you decide to use.
  
  • Ex: if you are interested in studying the visual ability of birds of prey, you are limited to studying birds such as eagles, vultures, hawks, and owls;
  • Ex: If you wanted to study hallucinations or delusions, you have limited the participants to those who experienced both of those phenomena and can communicate to you

Question 2

Number of Participants

Answer 2

When deciding how many participants you should use, there are a few factors to take into account.

NUMBER OF PARTICIPANTS:

• FINANCES – Do you have the funding for 30 or 3,000 participants?
• TIME – Do you have enough time to interview 500 participants?
• AVAILABILITY – Are there enough participants available?
• AMOUNT OF VARIABILITY – the more variable you expect the results to be within a group, the larger the number of participants in order to get an accurate representation of the target population. This variability is called a NUISANCE VARIABLE.
  
  • To create more HOMOGENEOUS groups and reduce the effect of the NUISANCE variable:
    
    • Use STRATIFIED RANDOM SAMPLING
• POWER – The number of participants tested is related to the POWER of our statistical test. Power is the likelihood (probability) that the statistical test will be significant (i.e., the experimental hypothesis is accepted when it is true). Generally speaking, the greater the number of participants, the higher the power of the statistical test; therefore, it is to your advantage to use as many participants as possible under the specific constraints of your research.

Question 3

Apparatus

Answer 3

You need to consider the type of apparatus, if any, you will be using,

Apparatus can both present the independent variable and record the dependent variable.

Often, the nature of your IV can help determine what apparatus you need. Ex) A college student was interested in studying the effects of noise on recall and spatial tasks. He played a white noise and a popular song both at the same decibal, measured by a digital sound meter.

APPARATUS: Literally the equipment used to apply the Independent Variable.

• Ex: the administration of a particular type of light will require a specialized projector. Presenting food to a hungry rat that has learned to press a lever could involve the purchase of an expensive Skinner box or a food-pellet dispenser.
  
  • Often the nature of the Independent Variable will influence the type of apparatus you choose to use.
• DEPENDENT VARIABLE RECORDING
  
  • You do not want the researcher’s presence to interfere with or modify the participant’s behavior. But that might make it difficult to record the effects on the Dependent Variable.
  • Record the DV in the best way that you can given your budget.

Question 4

Experimenter as an Extraneous Variable

Answer 4

Both the physiological and psychological attributes of the experimenter can influence the outcome of your research. Research shows that the experimenter’s age, sex, and race are all variables that can have an influence on participants’ responses.

Robert Rosenthal (1977) has shown that male experimenters are more friendly toward participants than female experimenters.

The experimenter’s expectations concerning the participants’ behavior can, and do, affect performance. Expectations cause him or her to behave toward the participants in such a manner that the expected response is, indeed, more likely shown. The experimenter is literally a cause of the desired or expected response.

To decrease or eliminate experimenter expectancies altogether, experimenters should carefully prepare instructions so their manner of presentation will not influence the participants’ responses.

Instructions concerning participants’ responses should be as objective and concrete as possible. If they are subjective then there is room for experimenter expectancies to dictate how they will be scored.

Instructions could also be recorded prior to the experiment and are told to participants through the recording.

Another method is to use a single-blind experiment. In this type of experiment, the experimenter is unaware of the treatment the participants are receiving.

EXPERIMENTER AS AN EXTRANEOUS VARIABLE:

• EXPERIMENTER CHARACTERISTICS – Both physiological and psychological attributes of the experimenter can influence the outcome of your research (race, Gender, Attractiveness, Assertiveness, etc.)
• EXPERIMENTER EXPECTANCIES – the experimenter’s expectations concerning the participants’ behavior can, and do, affect performance. The experimenter’s expectations cause him or her to behave toward the participants in such a manner that the expected response is, indeed, more likely shown – also called the ROSENTHAL EFFECT. (Occurs in both humans and animals).
• CONTROLLING EXPERIMENTER EFFECTS – The most common procedures for controlling general experimenter characteristics are to:
  
  • Use standardized methods
  • Use careful training to a set standard when the experimenter administers procedures
  • Standardize appearance, attitude, and so forth as much as possible
  • Try to REPLICATE the findings with a different experimenter.
• CONTROLLING EXPERIMENTER EXPECTANCIES:
  
  • The instructions that the experimenter gives to the participants should be carefully prepared so their manner of presentation will not influence the participants’ responses.
  • Use instrumentation and automation to provide instructions to participants. No experimenter means no experimenter expectancies.
  • Conduct a SINGLE-BLIND experiment, which keeps the experimenter in the dark regarding which participants receive which treatment(s).

Question 5

Participant Extraneous Variables

Answer 5

Demand characteristics are features of an experiment that inadvertently lead participants to respond in a particular manner. The experimenter can have an influence, as well as, the experimental context, or IV manipulation.

The desire to cooperate and act as the participants believe the experimenter wants them to is called the good participant effect

PARTICIPANT PERCEPTIONS AS AN EXTRANEOUS VARIABLES:

• DEMAND CHARACTERISTICS and GOOD PARTICIPANTS:
  
  • Recall DEMAND CHARACTERISTICS – When participants use cues in an experiment to determine what the experimenter’s hypothesis is and how they are supposed to act.
  • GOOD PARTICIPANT EFFECT – The desire to cooperate and act as the participants believe the experimenter wants them to.
• RESPONSE BIAS:
  
  • YEA-SAYERS – tend to answer ‘Yes’ to all survey questions even if they contradict themselves.
  • NAY-SAYERS – tend to answer ‘No’ to all survey questions even if they contradict themselves.
  • RESPONSE SET – When the experimental context in which the research is being conducted causes participants to respond in a certain manner.
    
    • Ex: When going for a job interview, applicants all take cues from the interviewer and the surroundings. In some cases, they will need to be highly professional; in other situations, they can be a bit more relaxed.
    • Even the questions themselves may create a response set.
      
      • Ex: How questions are worded or their placement in the sequence of items may prompt a certain type of response; it may seem that a socially desirable answer is being called for.

Question 6

Response Bias

Answer 6

Yea-sayers are people with the tendency to answer yes for everything

Nay-sayers are people with the tendency to answer no for everything

Response set is when the experimental context or situation in which the research is being conducted can cause participants to respond in a certain manner. Ex) At a job interview you take cues from the interviewer and your surroundings. Sometimes you will need to be very professional and other times you can be more relaxed

Question 7

Culture

Answer 7

INTERFACE BETWEEN RESEARCH AND CULTURE: The goal of cross-cultural psychology is to determine whether research results and psychological phenomena are universal.

• Features that differentiate one culture from another are ENDURING attitudes, values, and behaviors transmitted from generation to generation.

CULTURE, KNOWLEDGE, and TRUTH:

• ETIC – A UNIVERSAL TRUTH
• EMIC – A CULTURE-SPECIFIC TRUTH
  
  • There are many more EMICs than ETICs
  • A Problem with Researchers is that researchers often become ETHNOCENTRIC – they view other cultures as an extension of their own. But most psychological research is looking for UNIVERSAL TRUTHS.
  • Another problem is that western researchers probably consider the fundamental attribution error (in which actions are attributed to the individual even in the face of compelling situational cues), to be a universal finding.

EFFECT OF CULTURE ON RESEARCH:

• CHOICE OF THE RESEARCH PROBLEM – culture clearly dictates the nature of the research project; some problems are important in one culture but not in another.
  
  • Ex: The study of individual achievement motivation is a topic of considerable interest and importance in an individualistic society like the United States, it would be a less important research topic in a collectivist society like China.
• NATURE OF THE EXPERIMENTAL HYPOTHESIS – When you have selected a problem that is relevant beyond your own culture, you must still deal with the experimental hypothesis, which could cause further cultural issues.
  
  • Ex: Even though the study of factors that determine one’s personal space is relevant in a number of cultures, the creation of an experimental hypothesis that applies to all cultures will be most difficult due to the vast differences that cultures have regarding the requirement for ‘personal space’.
• SELECTING THE IV and RECORDING THE DV – This is most relevant depending on technological use and availability.

CULTURE: METHODOLOGY AND ANALYSIS ISSUES:

• PARTICIPANTS AND SAMPLING – is the sample of participants representative of the culture from which they were drawn?
  
  • Assuming you can satisfy the requirement that a sample is representative of its culture, you are likely to be faced with an equally difficult task: being able to ensure that samples from two or more cultures are equivalent before conducting the research.
    
    • Ex: You can’t assume that 2nd-year college students in the US and those in Thailand are equivalent.
• TYPE OF SURVEY AND QUESTIONNAIRE – Surveys used cross-culturally present several issues.
  
  • Translation – how do you know it was translated with proper meaning? Do a BACK-TRANSLATION to read the translation of the translation.
  • Questionnaires made for one culture almost always have a cultural bias or implied meanings that are either non-translatable, irrelevant, nonsensical, or even offensive to other cultures.
• CULTURAL RESPONSE SET – Tendency of a particular culture to respond in a certain manner.
  
  • If differences exist among the groups tested in various cultures, a cultural response set may be operating.

Question 8

Controlling Participant Effects

Answer 8

CONTROLLING PARTICIPANT EFFECTS:

• DEMAND CHARACTERISTICS – When participants use cues in an experiment to determine what the experimenter’s hypothesis is and how they are supposed to act.
• DOUBLE-BLIND EXPERIMENTS – Experiments are conducted in which both the experimenter and the participants are unaware of which treatment is being administered to which participants.
  
  • Controls for both PARTICIPANT EFFECTS and EXPERIMENTER EFFECTS.
• PURPOSELY DECEIVE ALL PARTICIPANTS – rather than allow the participants to guess what the purpose of the study is, allowing some to guess wrong and others guess correctly, creating a NUISANCE VARIABLE. Deceiving EVERYONE equally gets rid of this variable.
  
  • However, the information used to deceive the participants may result in erroneous guesses about the nature of the experiment; the participants are then responding to the demand characteristics created by the deception.
• CONTROLLING FOR YEA-SAYING – The most typical control for yea-saying (and nay-saying) is to rewrite some of the items so that a negative response represents agreement (control for yea-saying) or a positive response represents disagreement (control for nay-saying).
• SAFEGUARDING AGAINST THE RESPONSE SET – Review all questions that are asked or items to be completed to determine whether a socially desired response is implied in any manner.